Fluorescent lamp discharge tube having electrostatically coated envelope
US4914723A · kind A · utility
4Cited by
5References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1987 |
| Grant date | Apr 3, 1990 |
| Priority date | — |
| Expiry date | Dec 28, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/225
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fluorescent lamp discharge tube has an electrostatically coated envelope. The coating comprises a mixture of 100 parts by weight of phosphor, 0.01 to 3 parts by weight of a fatty acid having a melting point greater than 40.degree. C. or the ammonium, aluminum alkaline earth salts thereof, and 0.05 to 5 parts by weight of finely divided aluminum oxide having a grain size smaller than 0.1 micron. The phosphor is applied to the tube by a venturi effect and results in a more uniformly applied coating than is provided using a suspension coating. Uniformity of the coating is measured by the disclosed optical densitometry test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.